The current project was designed to further our knowledge of the nature of schizophrenia by a longitudinal investigations of the following questions about schizophrenic cognition: 1) Are there fundamental or primary features (which are always present) in schizophrenic thought disorders? Do specific types of thought disturbance differentiate patients into "true" schizophrenics and reactive psychoses? 2) Are thought disorders primary symptoms which persist when the patient is in the recovery stage? What is the longitudinal history of a thought disorder? 3) Do cognitive controls and/or the extent of thought disorders have prognostic significance, and predict the schizophrenic's subsequent clinical course? The research involves a multifaceted longitudinal investigation of schizophrenic thought disorders and cognitive controls using a pretested battery of performance tests, projective tests, cognitive measures, taped interviews, patient self-ratings and staff behavioral ratings. These will assess idiosyncratic thinking, associative thinking, overinclusion, the abstract-concrete dimension, logical and autistic thinking, boundary disturbances, primary process drive-related content, scanning, field articulation, and other aspects of cognition. Three samples of schizophrenic and nonschizophrenic patients will be assessed at four time periods, lasting up to 8 years for one subsample. Patients will be evaluated in the hospital at the acute stage, during partial recovery, and then followed up at varying time periods during the posthospital period, in terms of potential disordered thinking, level of psychotic and neurotic symptoms, rehospitalization, personality variables, and social and work adjustment.